For a community suffering from collective trauma, unity is vital for building community resilience, which is the capacity to withstand, recover from, and respond positively to a collective crisis. Both the Native American Tulalip community and the predominantly White Marysville community were affected by an October 2014 school shooting in which five students (3 Native American; 2 European American) died. We sought to identify factors that contribute to community resilience. We surveyed 597 employees of the Marysville School District and assessed perceptions of unity prior to and after the shooting, as well as personal experiences following the shooting (i.e., negative and positive feelings). My project focuses on the relation between people’s individual experiences and their perceptions of community unity following the shooting. I conducted a series of regression analyses predicting unity from personal experiences and found that people who had more positive feelings following the shooting perceived the communities as more united, while people who had more negative feelings perceived the community as less united. Furthermore, these relationships were magnified among people who knew at least one victim of the shooting compared to those who did not know victims. These findings suggest that in cases of collective trauma, projections of negative feelings following the event have the potential to hinder efforts to rebuild the community, whereas positive feelings may serve to aid this effort, especially among people who are closely tied to the traumatic event. These results highlight the importance of understanding how to foster positive feelings in the promotion of post-trauma healing. Given the frequency of mass violence in contemporary society, it is increasingly important to examine not only preventative measures but also understand how to promote healing for those affected by these tragedies. This work seeks to begin answering this question.

The Cretaceous-Paleogene (K-Pg) mass extinction and resulting biotic recovery mark a pivotal moment in mammal evolution. The recovery period, which spanned about 1 million years from the Puercan North American Land Mammal Age (NALMA) to the Torrejonian NALMA, represents a transition from species-poor “disaster” faunas directly following the extinction event to species-rich “recovery” faunas. Though previous research has broadly studied the faunal dynamics of the early Paleogene, the exact mode and tempo of the biotic recovery has not been well examined. To investigate the ecological trends of the “disaster” to “recovery” faunal transition, specifically changes in diet, we analyzed dental evolution within the periptychid and arctocyonid “archaic ungulate” lineages over a time period that spans from the Puercan NALMA to the Torrejonian NALMA. We measured relief index (RFI), a metric that determines the ratio between the 2D and 3D area of mammal teeth, on both the “archaic ungulates” and a set of ecologically diverse extant mammals to identify the dietary ecologies of the extinct mammals. Previous research has demonstrated a correlation between RFI and diet in extant mammals; high RFI values correspond to herbivory and insectivory, while low RFI values correspond to omnivory and frugivory. Our preliminary results suggest an increase in dietary diversity and an overall decrease in RFI during the biotic recovery. This reduction in RFI reflects a trend in “archaic ungulate” dietary preference from insectivory in the Puercan NALMA to omnivory and frugivory in the Torrejonian NALMA. The results of our study will help scientists understand how ecosystems recover from catastrophic events, such as mass extinctions, on large timescales.

Honeybees (Apis mellifera) use a caste system to organize individuals into different roles. The queen is the only bee in the hive to ingest royal jelly and the only fertile female. Many sterile workers perform different jobs in their short lives, moving from larvae-nurse to keeping the hive clean to foraging for food. At each stage the worker bees learn a new task. Such different phenotypes and behavior would indicate a difference in gene expression in the brain. In a population of organisms that are genetically similar, these changes in gene expression must be explained in chemical modifications of the genome, or the epigenome. Thus far, much attention has been given to DNA methylation as an epigenetic feature known to be associated with variation in gene expression. Royal jelly, however, contains butyrate, a histone deacetylase inhibitor, which suggests that histone tail modifications could be a major mechanism for regulating gene expression in queen bees. To further investigate the role of histone modification in determining honeybee caste division, we are performing chromatin immunoprecipitation with massively parallel DNA sequencing (ChIP-seq) to profile key chromatin modifications: H3K27ac, and H3K27me3. H3K27ac and H3K27me3 are histone modifications that have opposing effects; where H3K27ac marks active regions of the genome, and H3K27me3 is indicative of repressive chromatin. We anticipate when using ChIP-seq to map chromatin modification in the brains of queen and worker bees, we will observe key differences in genome regulation and be able to identify genes important to honeybee behavior. As an initial step toward achieving our goal, we describe the chromatin state of brains from forager honeybees.